Red Bull headed to Singapore undefeated this season, with the twisty and bumpy street circuit touted as the team's biggest obstacle towards taking an unprecedented clean sweep of race wins in 2023.
Friday practice provided more evidence of Red Bull's potential struggles, with Sergio Perez and 2023 dominator Verstappen stuck down in seventh and eighth respectively, seven tenths behind Ferrari's pacesetter Carlos Sainz, as both drivers were sliding around in their RB19.
Verstappen admitted Red Bull's practice pace was even worse than it had envisaged, citing a lack of balance.
"A little bit worse than expected today," Verstappen said. "I just struggled a lot with the balance of the car.
"We tried quite a few things in FP2. Some worked, some didn't but we never really got the car together, so quite a few things to figure out for tonight.
"Just a few things that we don't understand, so that's what we have to look into."
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When asked if Ferrari's table-topping pace was surprising and made it a big threat for pole, Verstappen said: "Ferrari is very fast, I think we're just way worse than we expected. We'll try of course to improve but it's quite a big gap."
Perez encountered similar issues in practice trying to keep the RB19's rear end pointing in the right direction.
He noted that the Milton Keynes team's problems are mainly related to extracting one-lap pace out of its machinery, with fewer concerns over its race simulations.
However, overtaking will prove trickier on the modified Marina Bay layout than on most other circuits if the team starts out of position.
"I think there are some interesting bits going on that we need to figure it out overnight hopefully," the Mexican added.
"We seem to be struggling a little bit with the rear end of the car, especially in FP2, so plenty of things to look at. Hopefully, we can come up with the best possible set-up because we know qualifying is very important.
"We did expect the Ferrari to be very strong around here. We're just too far away, so hopefully tomorrow we are able to close the gap a bit more. But it's quite a challenge.
"Over a race distance we're looking good, but that doesn't count for much round here. We need to find the balance to be quick over one lap."